Java HTTP Caching Libraries?

So I need to improve out caching support and I really don’t want to got through all the pain myself if I can avoid it. Does anyone know of an existing library that just handles client-side caching with the appropriate If-None-Match and If-Not-Modified headers etc. We already have libraries for doing the actually HTTP stuff, I really just need something that knows how to store things on disk and tell me what headers to use to make the request conditional. Oh and we’re an applet so small and without dynamic loading or configuration files would be ideal.

It seems to me that all the advice on caching around the web focuses on the server-side and assumes the only that that would ever do client-side caching is an existing browser. Not overly helpful.